intercooler waterpump info
Posted: Sun Jul 15, 2001 10:51 pm
Yo dudes, I see a few more of you are coming over to my way of thinking to go
the extra hassle of an air-to-water cooler install. I likewise see a lot of
the same questions I had when trying to figure out what I would do about a
pump. Here is a bunch of pump info and pump control info I have collected,
which from some of your questions, I believe will be of some small worth to
somebody out there. Please let me know if it is.
Twelve volt water pumps fall into two basic types - impeller and diaphragm.
An impeller pump is of the low pressure, high flow type. In operation it is
quiet with low vibration levels. A diaphragm pump can develop much higher
pressures but generally with lower flows. A diaphragm pump is noisy and must
be rubber-mounted in a car. Suitable impeller type pumps are used in boats as
bilge pumps and for deck washing. They are relatively cheap and have very
high flows - 30 litres a minute is common. However, they are not designed for
continuous operation and generally don't have service kits available for the
repair of any worn out parts. Diaphragm pumps are used to spray agricultural
chemicals and to supply the pressurised water for use in boat and caravan
showers and sinks. They are available in very durable designs suitable for
continuous running and have repair kits available. Flows of up to 20 litres a
minute are common and they develop enough pressure (45 psi) to push the water
through the front mounted radiator and heat exchanger without any problems.
The factory water/air intercooler system in the Subaru Liberty RS uses an
impeller-type pump rated at 15 litres a minute (all flow figures are
open-flow). It is automatically switched from low to high speed as required.
This is an ideal pump because it was designed by Subaru to circulate the
water in a water/air intercooling system! However, it is a very expensive to
buy new, but if one can be sourced secondhand it is ideal.
A cheap and simple impeller pump is the Whale GP99 electric pump. It is so
small that the in-line pump can be supported by the hoses that connect to it.
It flows 11 litres a minute and has 12mm (.47 = 7/16 in ) hose fittings. It
is 136 x 36mm (5.35 x 1.42 in) in size and is suitable for discontinuous
operation. This pump is available from marine and caravan suppliers.
Brett Middleton's MRT SULE125 High flow water pump for air to water
intercooler, Does not include mount mods or adaptor pipes. $409 AUS or about
half that $US
Bosch pump used on the air/water IC of the supercharged Ford Lightning $230
new $175 from Godfrey David DGodfrey@PEI-IDT.com
The Flojet 4100-143 4000 is a diaphragm pump suitable for water/air
intercooler use. The US-manufactured pump uses a permanent magnet brush-type
fan-cooled motor with ball-bearings and is fully rebuildable. The pumping
head uses four diaphragms which are flexed by a wobble plate attached to the
motor's shaft. The 19 litre/minute pump uses ¾ inch fittings and is 230mm
long and 86mm in (9.0 x 3.39 in) diameter. It is available from companies
supplying agricultural spray equipment.
The Flojet pump needs to be mounted either vertically with the pump head at
the bottom, or horizontally with the vent slots in the head facing downwards.
This is to stop any fluid draining into the motor if there are any sealing
problems in the pump head. At its peak pressure of 280 kPa (40 psi), the pump
can draw up to 14 amps; however, in intercooler operation the pressure is
vastly less and so the pump draws only about 5.5 amps at 12 volts. The pump
is noisy (as all diaphragm pumps are) but mounting it on a rubber gearbox
crossmember mount effectively quietens it. Note that these pumps are much
louder when mounted to the car's bodywork than they are when sitting on the
bench!
Pump Control Systems
As already indicated, there are a number of ways of controlling the pump
operation. The simplest is to switch the pump on and off with a boost
pressure switch. This means that whenever there is positive manifold
pressure, the pump circulates the water from the heat exchanger through the
radiator and back to the heat exchanger. If boost is used frequently and for
only short periods, this approach works well. However, it is better if a
timer circuit is used so that the pump continues to operate for a short
period after boost is finished.
A suitable pressure switch is an adjustable Hobbs unit, available from auto
instrument suppliers. However, this switch is relatively expensive and a
cheaper unit is easily found. Spa bath suppliers stock a pressure-operated
switch that is ideal for forced aspirated car use. The pressure switch is
designed to work as part of the air-actuated switching system which is used
in a spa bath so that bathers don't have to directly operate high voltage
switches. The switch triggers at around 1 psi and costs about half that of a
traditional automotive pressure switch. If a switching pressure above 1 psi
is required, simply tee a variable bleed into the pressure line leading to
the switch. Adjusting the amount of bleed will change the switch-on point.
Another approach to triggering pump operation is to use a throttle switch. A
micro switch (available cheaply from electronics stores) can be used to turn
on the pump whenever a throttle position over (say) half is reached. A cam
can be cut from aluminium sheet and attached to the end of the throttle
shaft. If shaped with care, it will turn on the switch gently and then keep
it switched on at throttle positions greater than the switch-on opening
throttle angle.
If a two-speed pump operation is required, the pump can be fed current
through a dropping resistor to provide the slow speed. When full speed is
required, the dropping resistor can be bypassed. Suitable dropping resistors
are the ballast resistors used in older ignition systems or the resistor pack
used in series with some injectors. The value of the resistor that is used
will depend on the pump current and its other operating characteristics. In
all cases, the resistor will need to dissipate quite a lot of power and so
will need to be of the high wattage, ceramic type. The resistor will get very
hot and can be placed on a transistor-type heat sink mounted within the
airstream, perhaps behind the grille. When experimenting with resistors and a
pump, you should know that placing the multiple resistors in parallel will
increase pump speed while wiring the resistors in series will slow the pump.
Another approach is to use a temperature switch, so that the pump doesn't run
when the intake air is not actually hot. This situation can occur on boost if
the intake air temperature is very low because the day is cold. Overly cold
intake air can cause atomisation problems, although this is not normally a
problem in a high performance car being driven hard! However, running the
pump when the intake air is perhaps only 5degrees is pointless and it can be
avoided by placing a normally-open temperature switch in series with the
boost pressure or throttle position switches. If the switch closes at
temperatures above (say) 30 degrees, the pump will operate only when it
actually needs to. A range of low cost temperature switches is available from
RS Components (stores world-wide). Note that in all pump control systems a
relay should be used to operate the pump.
Does any of this help anyone?
Larry Witherspoon
92 Turbo Legacy
Torrance (Los Angeles)
To unsubscribe from this group, please send an email to:
BC-BFLegacyWorks-unsubscribe@egroups.com
zZz <http://docs.yahoo.com/info/terms/> .
the extra hassle of an air-to-water cooler install. I likewise see a lot of
the same questions I had when trying to figure out what I would do about a
pump. Here is a bunch of pump info and pump control info I have collected,
which from some of your questions, I believe will be of some small worth to
somebody out there. Please let me know if it is.
Twelve volt water pumps fall into two basic types - impeller and diaphragm.
An impeller pump is of the low pressure, high flow type. In operation it is
quiet with low vibration levels. A diaphragm pump can develop much higher
pressures but generally with lower flows. A diaphragm pump is noisy and must
be rubber-mounted in a car. Suitable impeller type pumps are used in boats as
bilge pumps and for deck washing. They are relatively cheap and have very
high flows - 30 litres a minute is common. However, they are not designed for
continuous operation and generally don't have service kits available for the
repair of any worn out parts. Diaphragm pumps are used to spray agricultural
chemicals and to supply the pressurised water for use in boat and caravan
showers and sinks. They are available in very durable designs suitable for
continuous running and have repair kits available. Flows of up to 20 litres a
minute are common and they develop enough pressure (45 psi) to push the water
through the front mounted radiator and heat exchanger without any problems.
The factory water/air intercooler system in the Subaru Liberty RS uses an
impeller-type pump rated at 15 litres a minute (all flow figures are
open-flow). It is automatically switched from low to high speed as required.
This is an ideal pump because it was designed by Subaru to circulate the
water in a water/air intercooling system! However, it is a very expensive to
buy new, but if one can be sourced secondhand it is ideal.
A cheap and simple impeller pump is the Whale GP99 electric pump. It is so
small that the in-line pump can be supported by the hoses that connect to it.
It flows 11 litres a minute and has 12mm (.47 = 7/16 in ) hose fittings. It
is 136 x 36mm (5.35 x 1.42 in) in size and is suitable for discontinuous
operation. This pump is available from marine and caravan suppliers.
Brett Middleton's MRT SULE125 High flow water pump for air to water
intercooler, Does not include mount mods or adaptor pipes. $409 AUS or about
half that $US
Bosch pump used on the air/water IC of the supercharged Ford Lightning $230
new $175 from Godfrey David DGodfrey@PEI-IDT.com
The Flojet 4100-143 4000 is a diaphragm pump suitable for water/air
intercooler use. The US-manufactured pump uses a permanent magnet brush-type
fan-cooled motor with ball-bearings and is fully rebuildable. The pumping
head uses four diaphragms which are flexed by a wobble plate attached to the
motor's shaft. The 19 litre/minute pump uses ¾ inch fittings and is 230mm
long and 86mm in (9.0 x 3.39 in) diameter. It is available from companies
supplying agricultural spray equipment.
The Flojet pump needs to be mounted either vertically with the pump head at
the bottom, or horizontally with the vent slots in the head facing downwards.
This is to stop any fluid draining into the motor if there are any sealing
problems in the pump head. At its peak pressure of 280 kPa (40 psi), the pump
can draw up to 14 amps; however, in intercooler operation the pressure is
vastly less and so the pump draws only about 5.5 amps at 12 volts. The pump
is noisy (as all diaphragm pumps are) but mounting it on a rubber gearbox
crossmember mount effectively quietens it. Note that these pumps are much
louder when mounted to the car's bodywork than they are when sitting on the
bench!
Pump Control Systems
As already indicated, there are a number of ways of controlling the pump
operation. The simplest is to switch the pump on and off with a boost
pressure switch. This means that whenever there is positive manifold
pressure, the pump circulates the water from the heat exchanger through the
radiator and back to the heat exchanger. If boost is used frequently and for
only short periods, this approach works well. However, it is better if a
timer circuit is used so that the pump continues to operate for a short
period after boost is finished.
A suitable pressure switch is an adjustable Hobbs unit, available from auto
instrument suppliers. However, this switch is relatively expensive and a
cheaper unit is easily found. Spa bath suppliers stock a pressure-operated
switch that is ideal for forced aspirated car use. The pressure switch is
designed to work as part of the air-actuated switching system which is used
in a spa bath so that bathers don't have to directly operate high voltage
switches. The switch triggers at around 1 psi and costs about half that of a
traditional automotive pressure switch. If a switching pressure above 1 psi
is required, simply tee a variable bleed into the pressure line leading to
the switch. Adjusting the amount of bleed will change the switch-on point.
Another approach to triggering pump operation is to use a throttle switch. A
micro switch (available cheaply from electronics stores) can be used to turn
on the pump whenever a throttle position over (say) half is reached. A cam
can be cut from aluminium sheet and attached to the end of the throttle
shaft. If shaped with care, it will turn on the switch gently and then keep
it switched on at throttle positions greater than the switch-on opening
throttle angle.
If a two-speed pump operation is required, the pump can be fed current
through a dropping resistor to provide the slow speed. When full speed is
required, the dropping resistor can be bypassed. Suitable dropping resistors
are the ballast resistors used in older ignition systems or the resistor pack
used in series with some injectors. The value of the resistor that is used
will depend on the pump current and its other operating characteristics. In
all cases, the resistor will need to dissipate quite a lot of power and so
will need to be of the high wattage, ceramic type. The resistor will get very
hot and can be placed on a transistor-type heat sink mounted within the
airstream, perhaps behind the grille. When experimenting with resistors and a
pump, you should know that placing the multiple resistors in parallel will
increase pump speed while wiring the resistors in series will slow the pump.
Another approach is to use a temperature switch, so that the pump doesn't run
when the intake air is not actually hot. This situation can occur on boost if
the intake air temperature is very low because the day is cold. Overly cold
intake air can cause atomisation problems, although this is not normally a
problem in a high performance car being driven hard! However, running the
pump when the intake air is perhaps only 5degrees is pointless and it can be
avoided by placing a normally-open temperature switch in series with the
boost pressure or throttle position switches. If the switch closes at
temperatures above (say) 30 degrees, the pump will operate only when it
actually needs to. A range of low cost temperature switches is available from
RS Components (stores world-wide). Note that in all pump control systems a
relay should be used to operate the pump.
Does any of this help anyone?
Larry Witherspoon
92 Turbo Legacy
Torrance (Los Angeles)
To unsubscribe from this group, please send an email to:
BC-BFLegacyWorks-unsubscribe@egroups.com
zZz <http://docs.yahoo.com/info/terms/> .